Vehicle Facts

49 / 47MPG

After first appearing in 2014-2015 and then taking model year 2016 off, the Honda Accord Hybrid is back at dealers as a refreshed 2017.

Honda’s car faces fierce competition from the Ford Fusion, Toyota Camry, Hyundai Sonata, and Chevrolet Malibu mid-sized hybrids, but it comes back still at the top of its class for EPA mpg, total system horsepower, and at least matches key specs in other areas like acceleration, ride, interior space and comfort.

Positioned as a bit of a range topper however, it has yet to grab the mainstay market share from the Fusion Hybrid which leads the mid-size hybrid sedan segment, trailed by the Camry Hybrid.

This new version with 49 mpg city, 47 highway, and 48 mpg combined is a little more efficient than the 2015 version which was rated 50 city, 45 highway, and 47 mpg combined. Honda also says that under new EPA testing guidelines, the previous Accord Hybrid’s 50 mpg would have been 48 now. Total system power combining the gas engine with the electric motor and battery pack is now 212 horsepower (158 kW) for a gain of 16 horses since 2015.

Launch time for 0-60 mph is expected to be in the low-7-second range, though Honda did not provide an official number.

The hybrid Accord, available in three well-equipped trims, is now being manufactured closer to key hybrid part suppliers in Sayama, Japan rather than in Honda’s Marysville, Ohio factory. Honda executives say they plan to double production for the U.S. market from roughly 14,000 cars made for model year 2015 to near 30,000 in 2017.

An afternoon drive through vineyard roads, winding hills, and a mostly flat interstate highway in California’s Napa wine country let the Accord strut its stuff.

Already a competent handler, the front suspension received a new bushing design to mildly improve the balance between bump compliance and control. Revised power steering assistance also adds to the consistent sure-footed feeling. Cornering through curvy hills felt planted with minimal roll while comfy but ample seat bolstering held the driver and a passenger in place through the curves.

The hybrid shares almost all of its core specifications with its conventional twin. The larger-than-compact size allows the Accord and its peers to carry four passengers and their luggage with ease on a road trip, and five can be accommodated in a reasonable fashion. Outside, subtle blue tints to the front and rear lamps along with a hybrid label mark its electrical heritage. Inside, all of the usual fit and finish of the strong-selling conventional Accord carry the day. The hybrid adds only minor changes to the interior display screens. A new touch-sensitive center display added in 2016 supports Apple CarPlay and Android Auto integration with the leading smartphones. Ample front and rear head and legroom are similar to its competitors.

In terms of accessories and feature content, the base Accord Hybrid is roughly comparable to the non-hybrid Accord EX trim plus the Honda Sensing package of advanced safety features. The Sensing package in every hybrid Accord includes camera and radar-based features like Lane Departure Warning, Lane Keeping Assist, Forward Collision Warning, Collision Mitigation Braking, and Active Cruise Control. Yet, the hybrid base MSRP went up only $300 to $29,605 from the 2015 model. Other hybrid trims include the EX-L starting at $32,905 with leather seating and moonroof. The Touring trim starts at $35,955 and adds LED headlights, parking sensors, rain-sensing windshield wipers, and built-in GPS navigation. The non-hybrid EX trim starts at $25,730 without the Honda Sensing package. Add to these respective prices an $835 destination fee to arrive at actual starting sticker MSRP.

The Accord Hybrid leads the pack in EPA mileage with its unique “Two-Motor” powertrain using two electric motors, a clutch, and a single fixed gear ratio instead of a conventional multi-speed or Continuously Variable Transmission (CVT) between the engine and wheels.

Known as the Intelligent Multi-Mode Drive (I-MMD), it acts as a virtual CVT. It can move the car entirely on battery power at modest acceleration during an initial launch from a stop or at other times under low torque demand and when slowing the car by regenerating electricity back into the 1.3-kWh lithium-ion battery. When the battery doesn’t have enough power or energy to drive the car alone, the somewhat smaller of the two electric motors is used to spin up and start the gas engine. Once running, the engine can spin the smaller motor to generate electricity for use by the larger motor (known as series “Hybrid Mode”). Or, a clutch can connect the gas engine with the larger electric motor so both can physically work together to spin the wheels and move the car. These three operating modes are referred to by Honda as “EV Drive,” “Hybrid Drive,” and Engine Drive.” The car’s hybrid powertrain computer automatically switches between these modes while driving.

Other carmakers tend to use either a power-split or parallel-only hybrid design. In fact, Honda itself has used a parallel hybrid design known as IMA or Integrated Motor Assist since 1999 but is now phasing it out in favor of a similar system for small cars that it refers to as a “One-Motor” hybrid design. The one-motor system has not yet been introduced in the U.S. market but is used for a hybrid Fit subcompact in Japan – which gets slightly better mpg than the Japan-market Toyota Aqua, known in the States as the the Prius c. The difference between IMA and the Honda one-motor design is an added clutch between the engine and electric motor to allow more all-electric operation at low speeds. Other makers of parallel power trains include Kia, Hyundai, and Volkswagen (which just recently withdrew its Jetta hybrid from the U.S. market).

2017 Honda Accord Hybrid Chief Engineer, Koji Ninomiya.

The parallel approach uses just a single electric motor alongside the gas engine together with a multiple gear transmission of some kind. Honda has offered manual and mechanical CVT transmissions while Hyundai has used conventional automatics and Volkswagen has used a dual-clutch (DCT) automatic manual. Toyota, Ford, and GM instead use a variation of a power-split design that allows some power to flow mechanically and some electrically when the gas engine is running via a planetary gear arrangement that allows for a continuous range of effective gearing ratios between the engine and the wheels.

According to the Honda Accord’s Chief Engineer, Koji Ninomiya, the key advantage of Honda’s two-motor approach over the power-split design is its simpler gearing which can reduce internal transmission friction losses by as much as 50 percent. Its key weakness is the need for two large electric motors for generating and for traction (moving the car) and their associated battery DC-to-AC power inverters which results in higher cost. In the long-run, he says the added inherent costs won’t be a problem and it saves on the need for a full hydro-mechanical transmission.

The Accord Hybrid’s two motors are the 181 horsepower (135 kilowatts) traction motor and the 142 horsepower (106 kilowatts) generator motor. The generator closely matches the peak output of the 2.0 liter gas engine but the larger traction motor can also draw at least 30 horses (23 kilowatts) from the hybrid battery during acceleration.

The motors and power inverters in power-split hybrid designs can be nearly half that capability and the Hyundai’s single motor parallel-only design with a full automatic transmission uses an electric motor with only 51 horsepower (38 kilowatts). Hyundai says it will have leading EPA ratings for the smaller Ioniq model which uses that system when it arrives late this year at U.S. dealers (although early reviews in South Korea say it is weak on acceleration).

Honda’s Ninomiya said the hybrid Accord has only a 44 pound (20 kilogram) gain in weight from the non-hybrid 2.4 liter engine and mechanical CVT versus the hybrid’s 2.0-liter engine with motor inverters and its two-motor transaxle. Another 89 pounds (40 kilograms) are added by addition of the hybrid battery in the trunk.

The hybrid’s 2.0-liter Atkinson cycle engine has no accessory or other belts and uses a chain drive for the overhead cam so no regular rubber belt replacements are needed. Aluminum is used for the vehicle hood, the engine and transmission subframe and the steering knuckles (and the engine).

Honda improved the 2017 hybrid powertrain in multiple ways over the 2014-2015 model years. The gas engine itself is mostly unchanged, but the two separate stages of the catalytic converter were closely merged next to the engine and the old second stage of the catalytic converter was replaced with Honda’s new first-time exhaust heat recovery system module. This unit, like the one pioneered by Toyota’s Prius and a similar design recently added to the Chevrolet Malibu Hybrid, can use heat from the gas engine exhaust to help quickly bring up the engine coolant to its optimal operating temperature to maximize “cold start” engine efficiency and quickly provide cabin heating in winter conditions.

During the test drive through Napa, the Accord Hybrid’s engine spun up to a noticeable rpm but in a restrained and quiet manner no doubt helped out by the car’s active noise cancellation system that generates sounds that muffle the engine revs in both the conventional and hybrid models. The fixed gear ratio of the gas engine to the wheels is about the same as the conventional model’s manual transmission in its top 6th gear. The conventional automatic has a sixth gear with a lower “overdrive” ratio that spins the engine noticeably slower — at 75 mph the conventional automatic would have the engine at 2176 rpm versus 2764 rpm in the hybrid.

The Accord’s eco big brother, the mid-size Clarity model, is a separate platform supporting a hydrogen fuel cell powertrain later this year. A battery electric Clarity system with an as-yet undisclosed battery capacity and driving range arrives in the summer of 2017 and a plug-in hybrid Clarity with at least 40 miles of range and a gas engine based on the Accord Hybrid’s 2-motor system arrives in the fall of 2017, according to Steve Center, vice president of Environmental Business Development for Honda’s American operations.

Honda also redesigned the Accord’s electric motors and inverter circuitry for the new model year. The motors now use square instead of round wire for more space-efficient motor windings similar to Toyota’s new Prius Prime and like General Motors has done in recent years in the Chevrolet Volt, Spark EV, and now Bolt EV. This and other changes shrunk Honda’s motor size and weight by 23 percent while slightly increasing torque output and increasing horsepower by about 8 percent. Another primary goal of these optimizations was to allow use of this hybrid drive in multiple vehicle platforms spanning sedans and minivans. Honda also wanted to reduce the cost by physically shrinking the large motors. In the updated design,the traction motor now runs at near 700 volts which allows for the use of smaller wire windings and increases efficiency. Circuitry steps up the DC voltage from the battery pack’s nominal 266 volts.

The battery cells are from Blue Energy, a company jointly created and owned by Honda and battery maker GS Yuasa. For 2017 the cells, pack, and associated battery circuitry were redesigned which resulted in an overall pack size reduction of 33 percent and a weight reduction of almost 13 percent. This added 0.8 cubic feet of room to the car’s trunk versus the 2014-2015 model year design giving it an extra three-plus inches of depth for a leading 13.5 cubic feet among hybrid mid-size sedans although some of that is in an area above the pack which may be harder to utilize. The pack sits at the back of the trunk next to the rear seats and prevents them from folding down so there is no possibility of pass-through to the cabin area.

During the Napa drive the Accord hybrid’s brakes were linear and consistent unlike some hybrids from yesteryear that sometimes felt mushy or transitioned awkwardly from electric regeneration to friction braking. The driver can freely move the shifter between the normal “D” forward drive and “B” which adds stronger regenerative braking when the accelerator pedal is released and also when the brake pedal is pressed. Cruise control can only be engaged in D. If the battery fills up due to regenerative braking in B the car will dissipate the energy by using the generator to spin the gas engine (known as “engine braking”) rather than using the friction brakes on the wheels.

Although Honda’s hybrid system operated flawlessly during our test drive, we did notice that hard acceleration on the freeway resulted in about a two-second delay between foot down and the resulting surge of power as the car switched from its parallel “Engine Drive” to its “Hybrid Drive” series mode. This lag followed un-clutching the engine from the wheels so it can drive just the generator motor at whatever rpm is needed to supply the Accord Hybrid’s large traction motor. The effect was similar to a downshift in a conventional automatic transmission. Otherwise, transitions between drive modes were seamless. When the car is in steady state “Engine Drive” it uses only its gas engine and large traction motor – the smaller generator stays electrically neutral and spins freely.

Honda is using the same 2017 Accord hybrid powertrain in the hybrid version of the Odyssey minivan in Japan although it has no stated plans to bring this powertrain to the U.S. Odyssey model.

Before hitting the freeway we averaged 45.8 mpg in spite of some occasional spirited driving. Once on the freeway, we pushed the hybrid’s boundaries by repeatedly punching the accelerator to test passing situations from 55 to 80 mph and also drove at high speeds to test engine rpm cabin noise. The result was closer to 40 mpg for the second half of our test drive. Average easygoing drivers are likely to match the EPA estimates as long as they stay below 70 mph on the freeway.